Add annotationFilter to Ambassador Hosts

[RicardoNalesAmato]

This commit allows users to filter the Host resources based on
a given annotation using --annotation-filter.

This commit uses the same AnnotationFilter that is
already available (so a new type was not added) and already used
by many other source types.

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[seanmalloy]

/kind feature

[Raffo]

Can we add tests to this PR to test the filtering functionality?

[RicardoNalesAmato]

Can we add tests to this PR to test the filtering functionality?

Sure, I'll add that as soon as possible.

[njuettner]

Hello hello 👋🏻 , in general I'm fine merging this, however I'd like to see some tests added to the changes you made. Do you mind adding some tests to see if that works like expected?
Thank you ❤️

[k8s-triage-robot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
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/lifecycle stale

[RicardoNalesAmato]

/remove-lifecycle stale

[RicardoNalesAmato]

@njuettner @Raffo I completely forgot about this PR! I will be adding the tests this week. Are you guys still ok with merging this?

[KyleMartin901]

Sorry I was just searching the PRs for Ambassador and came across this one. I also created a PR for this feature as I only searched the issues 🤦‍♂️ to see if anyone else had issues with the annotation filter not working. I have added a bunch of tests to my PR so you can steal them if you would like. #2633

[RicardoNalesAmato]

Sorry I was just searching the PRs for Ambassador and came across this one. I also created a PR for this feature as I only searched the issues 🤦‍♂️ to see if anyone else had issues with the annotation filter not working. I have added a bunch of tests to my PR so you can steal them if you would like. #2633

Thanks @KyleMartin901 . If the implementation is the same and you've already added the tests I'd say let's try to get your PR merged instead.

[KyleMartin901]

@RicardoNalesAmato, our implementation is nearly identical. The filterByAnnotations function is identical and so is our addition of the annotationFilter to the NewAmbassadorHostSource we just implemented the Endpoints function a bit differently to get the same result.

I am happy either way if we use yours or mine would just love to have it fixed so won't have to maintain a fork with the patch 😀 You were first and have interacted with the team so happy to just have the tests added to your implementation so you maintain the credit for your work.

[RicardoNalesAmato]

@RicardoNalesAmato, our implementation is nearly identical. The filterByAnnotations function is identical and so is our addition of the annotationFilter to the NewAmbassadorHostSource we just implemented the Endpoints function a bit differently to get the same result.

I am happy either way if we use yours or mine would just love to have it fixed so won't have to maintain a fork with the patch 😀 You were first and have interacted with the team so happy to just have the tests added to your implementation so you maintain the credit for your work.

Thanks, @KyleMartin901! I'll copy your tests later today and will ping the team afterwards.

[alebedev87]

@RicardoNalesAmato : any particular reason why annotations are used for the filtering on the resources? Except for the historical one :)
The labels are better suited for filtering on Kube resources, the sources like service, ingress, etc. were enabled for the label filtering.

[KyleMartin901]

@alebedev87 currently the label filter doesn't support the Ambassador Host resource type are you suggesting modifying the PR to allow the Host resource type via the label filter?

For me, I missed that the label filter had been added as an option I was modelling my implementation off of the 3rd party sources like the Isto Gateway, and Contour HTTP Proxy that didn't have it enabled and I had only been using the annotation filter so totally missed it 😞.

I copied the existing implementations of 3rd party sources like the Isto Gateway, Contour HTTP Proxy etc. Should all the 3rd party sources be added to the label filter each individually by essentially copying what was done for service and ingress as done in the PR d91b7e6

[KyleMartin901]

@alebedev87 I just pushed an update to my PR f10f6eb so it now includes the label filter is that what you were looking for.

[alebedev87]

@KyleMartin901 : yes f10f6eb commit looks like what I meant by the label filtering.

However when I looked at the unit tests and saw that AmbassadorHost uses ingress.class annotation, kinda similar to the old way of specifying the ingress class for Ingress resource (before a dedicated API field appeared). I believe that the annotation filter of ExternalDNS was done partially for the reason to be able to filter Ingresses by the ingress class in the annotation. I'm wondering whether AmbassadorHost uses ingress.class annotation the same way Ingress used to. Then it may indeed make sense to keep the filtering by the annotation or think about the API enhancement for AmbassadorHost.
My guess is that the other implementations copied the ingress one without a lot of thinking of whether of they wanted to filter this way and whether it actually makes any sense to use not indexed part of the metadata.

[RicardoNalesAmato]

Hey @KyleMartin901 I was more busy than I expected last week and forgot to update this PR. Would you like to go with your PR instead as I see you’ve made some more changes, or shall I copy them to this one?

@alebedev87 In our case having that annotation greatly reduced the complexity of our Nginx to Ambassador migration. I believe that is the main reason why all other implementations Did the same thing. Could we perhaps move forward with this solution and refine it at a later date?

[KyleMartin901]

@RicardoNalesAmato i don't mind as long as we can get either one added I'll be super happy. If you don't have time I'm happy to go with mine but also happy if you want to cherry-pick the label implementation and just add the annotation tests.

[KyleMartin901]

@alebedev87 if you have any more information on what you like done to be able to get my PR merged in so an AmbassadorHost is able to be filtered would be awesome.

I used the ingress.class annotation within the tests just so the tests matched the other sources and the examples used for the AWS provider as I presumed most people would be looking at those for how it should be used, so I used them to keep it constant within the External DNS project.

The Ambassador Host resource itself doesn't use the ingress.class annotation to create an ingress route you must define an Ambassador Host and an Ambassador Mapping resource for any ingress to be created.

[alebedev87]

@KyleMartin901: cool, thanks for addressing my remark! I left a small review.
@RicardoNalesAmato : can we close this PR since we have Kyle's one?